Commonly a gun, nozzle, or wand which can be articulated by a human operator or integrated into an automatic application system. Spray bars and articulated nozzles are often used in automated spraying systems. Applicators are used to control the pattern, angle, droplet size, and intensity of the spray, and may serve as the point where two or more spray agents are finally combined.

Telescoping spray wand

Image credit: Northern Tool

Power source

A motor or piston is required to supply the compressor with its required actuation.

Light-duty electric pump

Image credit: Rittenhouse

Pressure source

The pump, compressor, or pressure generator increases the pressure of the carrier fluid or propellant (typically air) or directly pressurizes and moves the spray media.

Air compressor

Image credit: Garage Journal

Media

The spray system requires an agent to propel, and the system is limited to liquids, foams, and fine powders. For coatings with a hich viscosity, the media may need to be thinned in order to be spray-applied.

The system requires a container to hold the media so it can be integrated into a spray system. Some recepticles may be attached directly to the applicator, while others will serve as the pressure container. The reservoir should be resistant to corrosion from the material it is designed to hold.

Enclosures are manufactured to establish a regulated environment in which to apply surface coatings. This prevents overspray on equipment outside the enclosure, and also may incorporate a ventilation, dust collection, or other system for the best application results. Enclosures range from booths and hoods to garages for large-sized substrates. In many instances, this is not a required component.

Vehicle spray booth

Image credit: ATM Dyno

Handling or mounting equipment

Depending upon the application, a considerable amount of mobility may be required of the spray system. As such, systems may be positioned on a material handling truck or cart; a cargo truck, boom, or off-road vehicle; or a helicopter or airplane. Immobile spraying systems require a mounting effort as well.

Separators or reclaimers remove undersized powder, media and coarse waste. Reclaimed material can sometimes be recirculated back into the coating process if the media's particle size and coating characteristics still meet specifications.

Powder coating reclaim system

Image credit: Frederico Argento

Part loaders

In high volume spray applications it can be beneficial to have a conveyor or part placement system assist in moving unfinished and finished components between processes.

Part feeder

Image credit: Performance Feeders

Spray Technology

In general, sprays are atomized/distributed by one of the following means.

Air atomized

A paint application system wherein paint is atomized by combination with compressed air. It is a a system of applying paint in the form of tiny droplets in air, i.e., paint is broken down into droplets, or "atomized," by a spray gun as a result of being forced into a high velocity air stream. Shape and paint density of the resulting droplet cloud can be controlled by air pressure, paint viscosity, and gun tip geometry.

Airless

Paint spraying or application system using high fluid pressure to atomize paint by forcing it through a small orifice. System of applying paint, where paint under high pressure is passed through a nozzle and broken down into droplets, or "atomized," when it enters the lower pressure region outside the gun tip. (Less air is used than in conventional air spraying so that the problems of dry spray and paint bounce-back is reduced.)

Airless (air-assisted)

Air-assisted airless spray process is used to alter the spray fan shape pattern, but not to atomize the paint.

High velocity, low pressure

High velocity, low pressure (HVLP) spray guns atomize coatings utilizing a high volume of paint with low air pressure. HVLP spray equipment applies coating by means of a gun, which operates between 0.1 and 10.0 psig air pressure. A turbine produces the high volume of air. The lower pressure reduces paint viscosity, thus reducing bounce back, and increasing deposition efficiency.

Low pressure

Spray guns or spray equipment designed to operate under reduced pressure, while not requiring high volumes of air flow.

Rotary cup/disc

Rotary spray guns or applicators use a rapidly spinning cup/bell or flat disc to project powders or atomize paint. Rotary cup or bell rotary applicators produce a fan pattern, which is closer to a nozzle spray gun. A rotating head that is shaped to deliver paint forward in a circular pattern. The bell may be directed at any angle and be moved on robots or reciprocators, just as nozzle spray guns are. Disc rotary applicators spin the coating media out radially. Rotating heads that deliver paint horizontally 360° around the head are useful on an omega loop conveyer finishing lines. A disk is usually mounted horizontally on a vertical reciprocator. Disc rotary spray guns are also useful for internal or ID coating applications.

Ultrasonic

Ultrasonic atomization processes use a specialized transducer vibrating at ultrasonic frequencies to form a fine aerosol or mist of the coating material

Common Spray Systems

The following is an abstract of commonly used spray systems.

Aerosol can

Image credit: How Stuff Works

Aerosol cans are an exceptionally common way to dsitribute small amounts of surface coatings in a one-time use footprint. Solvents, paints, consumer products and many other products are sold in aerosol cans. The device is sold pressurized, and the operator controls the release, aim, and pattern of the spray with a nozzle.

Spray bottle

Image credit: American Printing Equipment

The spray bottle allows the operator to fill the reservoir with the agent of preference. High pressure is created within the reservoir through a trigger-like actuator, and the agent is fed and atomized through the nozzle.

Backpack sprayer

Image credit: Awesome Machines

Backpack sprayers are operator-mounted by the use of shoulder and waist straps. An enlarged reservoir that does not restrict mobilty is their main advantage over handheld sprayers. Backpack sprayers may be motorized or manual pump powered, and provide an applicator at arm's length.

Air gun sprayer

Image credit: TZ Manufacturing

Spray guns consist of a refillable reservoir integrated directly to the applicator, as well as a compressor to provide pressure in the system. These are most commonly used in painting applications, where a variety of nozzle tips allow the operator to select the spray pattern. A hose only links the gun to the compressor.

Truck/cart mounted

Video credit: Science Channel via YouTube

Spray systems are mounted on a truck or handling cart, such as the pressure washer in the video above. Cumbersome compressors, motors, and applicators are more easily maneuvered to a jobsite.

Conveyor spraying systems

Image credit: Bete

Spraying components in manufacturing settings apply a surface treating to a product. A spray bar is fixed over the production line to apply virtually any type of spray, including solvents like in a parts washer.

Spraying bays

Image credit: Asylum SFX

Spray systems where an immobile reservoir is hose-tethered to an applicator. These environments often suit automobiles or other large items, and may have sealing doors to prevent overspray onto nearby equipment. Drainage and reclaimation equipment is typically integrated.

Vehicle-mounted systems

Image credit: Crop Care Equipment

Vehicles are an effective means of applying sprays to a large or remote surface area. An onboard reservoir contains media for crop dusting, deicing, or—more rarely— firefighting and painting operations. If the vehicle is outfitted to spray while traveling, a spray mechanism on the underside or near the aft of the vehicle dispenses the agent. Other variants rely upon an operator with a handheld gun or wand to direct the spray while the vehicles is stopped. Systems for airplanes, helicopters, flatbeds, dumptrucks, boom lifts, ATVs, and trailers have been developed.

Spraying Safety

Exposure to spraying operations can be extremely hazardous, in part due to the small droplet size of the agent particles which are easy to inhale or affect eyesight. As such, proper respiratory equipment and other items of PPE are considered necessary equipment, sometimes by law.

Sprayers and Spraying Equipment Standards

It would be impossible to list all standards that could apply the equipment covered in this selection guide. However, ASTM E-1620 is perhaps most helpful when referencing industrial standards in regards to spray atomization and application equipment.

Spraying Applications

Spraying is process where a liquid or powder is distributed across an area by the means of pressurizing the spray agents and forcing it through an outlet. The outlet configuration determines the spray application. Spraying is a common process, notable applications including:

Spray painting: A spray system delivers paint, lacquer, stain, varnish, ink, or polyurethane to surface for aesthetic and functional purposes.

Agricultural spraying: Sprays are applied manually or by vehicles to an outdoor area to protect it from destructive pests, insects, or plants.

Powder coating: A surface finish where dry, granule, thermosensitive polymers are electrostatically applied to a metal object, where it is then heated into a uniform coating.

Flux spraying: Where an cleaning agent is spray-applied to the joint of base and filler metals that are to be welded, soldered, or brazed.

Lubrications spraying: Where industrial lubricants such as greases, oils, silicones and other compounds are spray-applied to zones with high mechanical friction.

Deicing: Salts, alchohols, or glycols are spread so as to remove ice and snow, and further inhibit the accumulation of it for a short period of time.

Cleaning: Cleaning is accomplished either by the means of a sprayable solvent which is then scrubbed, or by a solvent intermixed with a high pressure jet stream.

Pollution reduction: Spraying is the active mechanism for gas collection in pollution control wet scrubbers.

Related Products & Services

Coating and spray booths are enclosures used to contain spray coating processes such as painting, powder coating, thermal spraying, and other deposition methods. This category includes hoods, cabinets, tunnels and similar enclosures

Spray guns and applicators form a coating by directing atomized paints, adhesives, liquids, or powders toward a surface. These devices affect droplet sizes and spray patterns which influence the efficiency of the spray.

Paint spraying equipment and paint sprayers are used to atomize and propel a concentrated mist of a finish coating onto a surface. This includes the equipment used to directly apply the spray coating, as well as a variety of supporting equipment to optimize the painting process.